Writing instrument



FIG. 1 is a front, top isometric view of a writing instrument showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is front elevational view thereof;

FIG. 5 is a left side elavational view thereof, the right side elevational view being a mirror image thereof; and,

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a writing instrument, as shown and described. 